What verses in the Bible talks about “praying for the dead”?
There aren’t any.
It is a Catholic practice supported only by one verse (2 Maccabees 12:44) found in the Aprocryha which Protestants do not recognize as canonical. The Catholic Encyclopedia states the following:
“There is no clear and explicit warrant for prayers for the dead in the Scriptures recognized by Protestants as canonical.”
The Catholic Encyclopedia is correct.
“Praying for the dead” is wholly a Catholic practice “authorized” by their church tradition and council, not the Word of God.